PFAS Forever Chemicals: Health Effects, EPA Limits, and Where They Come From

97% of Americans Have PFAS in Their Blood—And the EPA Just Set Its First Drinking Water Limits

Per- and polyfluoroalkyl substances—PFAS—are a family of over 12,000 synthetic chemicals defined by their carbon-fluorine bonds, the strongest bond in organic chemistry. That bond is why they work so well: PFAS resist heat, water, oil, and degradation almost indefinitely. It is also why they accumulate in soil, water, wildlife, and human blood across the entire planet. The CDC's National Health and Nutrition Examination Survey found detectable PFAS in 97% of Americans tested. In April 2024, the EPA finalized the first national drinking water limits for six specific PFAS compounds—a regulatory milestone that had been blocked for decades by industry opposition and scientific uncertainty about thresholds.

The Chemistry of Persistence

PFAS are not a single chemical but a class defined by chains of carbon atoms bonded to fluorine atoms. The C-F bond has a bond energy of approximately 544 kJ/mol—among the strongest in nature. No naturally occurring enzyme can break it at environmental temperatures. This means PFAS that enter the environment in 1960 are still detectable in that same environment today. The most studied PFAS compounds are perfluorooctanoic acid (PFOA, eight-carbon chain, carboxylic acid end group) and perfluorooctane sulfonate (PFOS, eight-carbon chain, sulfonate end group), both of which were phased out of US manufacturing by 2002 and 2015 respectively—but are still detected globally due to their persistence.

Major Sources of PFAS Contamination

• Aqueous film-forming foam (AFFF): Used for decades to suppress fuel fires at military bases, airports, and petroleum facilities. AFFF is the single largest source of PFAS groundwater contamination in the US, with contamination documented at over 700 military installations.
• Non-stick cookware: Polytetrafluoroethylene (PTFE/Teflon) coatings on pans; PFAS-related processing chemicals (PFOA was used in Teflon manufacturing) are the exposure concern, not PTFE itself under normal use conditions.
• Food packaging: Grease-resistant coatings on fast-food wrappers, microwave popcorn bags, and pizza boxes leach PFAS into food, particularly when heated.
• Stain-resistant textiles: Scotchgard, Gore-Tex, and similar treatments on carpets and outdoor clothing shed PFAS through wear and washing.
• Industrial discharges: Manufacturing plants producing or using PFAS historically discharged into waterways; communities near former and current fluorochemical plants (e.g., near DuPont's Parkersburg, West Virginia facility) have extremely high drinking water contamination levels.

Health Effects: What the Evidence Shows

The International Agency for Research on Cancer classified PFOA as a Group 1 carcinogen (definitively causes cancer in humans) and PFOS as a Group 2A probable human carcinogen in 2023—a significant regulatory milestone that informs drinking water standard-setting globally.

The EPA's 2024 Drinking Water Rule

The EPA's April 2024 National Primary Drinking Water Regulation for PFAS set Maximum Contaminant Levels (MCLs) for six PFAS compounds. This is the first time the US has set legally enforceable drinking water standards for any PFAS compound.

• PFOA: 4 parts per trillion (ppt) — the lowest level reliably detectable
• PFOS: 4 parts per trillion
• PFNA: 10 ppt
• PFHxS: 10 ppt
• HFPO-DA (GenX chemicals): 10 ppt
• Mixtures of PFNA, PFHxS, HFPO-DA, and PFBS: hazard index of 1 (combined limit)

Water systems have three years to conduct monitoring, with compliance required by 2027. The EPA estimated that the rule will affect over 66,000 public water systems and reduce exposure for up to 100 million Americans. The cost of compliance—primarily filtration system installation and replacement—is estimated at $1.5 billion annually; the EPA estimated health benefits at $1.7–$2.8 billion annually.

Cleanup: The Chemistry Problem

PFAS contamination is extraordinarily difficult and expensive to remediate. Conventional biological wastewater treatment does not break C-F bonds. Activated carbon filters and reverse osmosis membranes can remove PFAS from drinking water but concentrate the removed compounds in a waste stream that still requires disposal. Thermal destruction requires temperatures above 1,100°C; incomplete incineration produces PFAS byproducts. Emerging destruction technologies include supercritical water oxidation, sonochemical degradation, and electrochemical oxidation—all of which show promise in laboratory settings but have not been demonstrated at the scale of contaminated aquifers.

The Defense Department has committed to replacing AFFF at all military installations by 2024 and is funding research into PFAS-free firefighting alternatives. Cleanup of existing groundwater contamination is expected to take decades and cost hundreds of billions of dollars nationally—costs being contested in litigation between manufacturers (primarily 3M and DuPont/Chemours) and contaminated communities and governments. In June 2023, 3M agreed to pay $10.3 billion to settle claims over PFAS contamination of public water systems in the US.

Health Disclaimer: This article presents scientific and regulatory information about PFAS and does not constitute medical or environmental advice. Individuals concerned about PFAS exposure or contaminated drinking water should contact their local health department or a qualified medical professional.